The pollination efficiency of the squash bee (Peponapis pruinosa) and the honey bee (Apis mellifera) on summer squash (Cucurbita pepo)

Observations were made and experiments conduct ed to ascertain if the specialized squash bee, P. pruinosa, is su perior to the honey bee as a pollinator of summer squash. Three parameters contributing to pollination efficiency are: the number of visits necessary to achieve pollination, the preference of the bees for staminate or pistillate flowers, and the average time spent foraging on a flower. Results of bagging and controlled-visit ex periments showed that individual visits to pistillate flowers by each species were equivalent. Honey bees displayed a significant pref erence for pistillate flowers; squash bees preferred male flowers. Squash bees worked the flowers more rapidly than did honey bees. When all parameters are considered, there appears to be little dif ference between the species as pollinators of squash. Where squash bee populations are strong, the use of honey bee colonies is su perfluous. In this study most pollination was accomplished by squash bees before honey bees appeared in numbers on the plant ing.